1. Field of the Invention
The present invention generally relates to an apparatus and method for providing an alignable, threaded sealed connection. The present invention is particularly useful in providing such a connection between two tubular members. More specifically, the present invention relates to an apparatus and method wherein a high pressure O-ring seal between mating male and female connectors is brought into sealing engagement with the aid of thrust transmitting threads which then disengage into interior thread relief grooves to permit relative rotation of the connectors for aligning and securing the connectors in a desired orientation.
2. Description of the Background
Seals which must withstand high pressure are employed in many environments. Many applications of high pressure seals are employed in the oil and gas drilling industry. For example, high pressure seals are used in the assembly of tubular devices intended for passage through boreholes in the logging of oil and gas wells. These devices typically employ a plurality of elastomeric, O-ring seals disposed in annular grooves about a male connector inserted within a cooperating female connector. These seals are used to protect the sensitive instruments, including the sensors and electronics, disposed within the logging tools from the harsh environment of the downhole location, including high pressure, high temperature and abrasive drilling fluids.
Because these large diameter, high pressure seals result in higher O-ring friction during assembly, a high assembly force is required. In the past, connections with those seals were simply assembled by forcing the connectors together and using brute force to overcome the high O-ring friction associated with the high pressure, large diameter seals. Although the mechanical advantages of threads in overcoming the O-ring friction was known, threads were not often used. Several reason exist for not employing a threaded make up. Where threads were employed to overcome the O-ring friction, it was not possible to align the connection as may be required after makeup. Accordingly, where an alignable connection was required, the advantages of a threaded makeup were unavailable. Further, threaded connections presented the risk that the threads might back off during use, causing separation of the connection and the possibility that a portion of the tool might be lost in the borehole.
Accordingly, there has been a long felt but unfulfilled need by the users of sealed connections, and particularly users in the oil and gas well logging industry where large diameter, high pressure seals are common, for an easily made up connection with the advantages, but not the disadvantages, associated with threaded makeup with the capability of aligning the connection to a desired orientation.